President Donald Trump trained his fire on members of his own party Thursday, declaring in the aftermath of the Republican's failed health care push that the conservative Freedom Caucus will hurt the entire GOP agenda. He vowed to "fight them" in 2018 if they don't get behind him.

The war of words spilling into West Michigan’s 3rd Congressional District. President Donald Trump's anger at the Freedom Caucus for posing as a stubborn impediment to his governing runs the risk of alienating the conservative base that fueled his rise during last year's Republican primaries and has - to this point - remained loyal to the president.

With his poll numbers falling and his plans to move onto tax reform and a robust infrastructure program imperiled, President Trump took to Twitter to attack the conservative group that many in the White House hold responsible for sabotaging last week's health care vote.

"The Freedom Caucus will hurt the entire Republican agenda if they don't get on the team, & fast. We must fight them, & Dems, in 2018!" Trump tweeted.

But as the White House considered flexing its muscle against the Freedom Caucus, the group remained unbowed, with several members sparring with a president whose agenda has stalled, whose approval ratings are hovering below 40 percent and who has been dogged by the ongoing probe into contacts between his associates and Russian officials.

"It didn't take long for the swamp to drain @realDonaldTrump," tweeted Rep. Justin Amash of Michigan. "No shame, Mr. President. Almost everyone succumbs to the D.C. Establishment."

Some Republicans seemed emboldened by the White House's prodding: Grand Rapids businessman Brian Ellis challenged Amash to a primary in 2014 and said Thursday he may do so again. "It's the same old thing with the Freedom Caucus: Don't let the perfect be the enemy of the good," Ellis said, adding "And for Amash to reject them is to not reflect what I know to be the desire of the constituents of this district."